An end wall panel is commonly a component of an arch-style steel building. Arch-style steel buildings are generally formed of three primary cold-formed steel components: the arch panels, which make up the basic shell of the structure; the end walls, which close in the front and rear of the structure; and the curved angle assembly, which serves as the attachment-point for the front and rear end wall to connect to the arch panels. All connections throughout this particular type of building system are usually accomplished by standard sized nuts and bolts.
In order to fabricate an arch-style steel building that is suitable for installation in locations that often experience high wind speeds (i.e. wind speeds in excess of 90 mph) without an internal framework, the end wall panel of the building must be light-weight and able to withstand high shear and bending loads. A problem associated with arch-style steel buildings is that the end wall panels currently used in such buildings do not offer sufficient strength for high-wind applications unless an interior framework is in place behind the panels. Further, the present panels are expensive to manufacture and have a low strength to weight ratio.
The end wall panel design currently used in many arch-style steel buildings, depicted in FIG. 1, is formed from a sheet of metal and consists of two upper flanges spaced apart from one another. Web sections, which act as stiffeners, extend from the two upper flanges at an angle to a lower flange. The “coverage dimension” of a panel (such as an end wall panel) refers to the distance between the centerlines of the outermost upper flanges of the panel. The current end wall panel with a coverage dimension of about 1.5 feet and 2 web sections, has a low moment of inertia and cannot withstand high wind loads. Also, the angle between the upper flange and the web section is generally about thirty-two degrees, which does not meet the American Iron and Steel Institute (AISI), North American Specification for the Design of Cold-Formed Steel Structural Members (NASPEC) 2001 Section B4.2. AISI NASPEC 2001 Section B4.2 defines the acceptable design dimensions for a flange stiffener used in cold-formed steel structures. Consequently, in order to comply with building codes, manufacturers are often required to supply an interior framework for installation behind the end wall panels in arch style steel buildings that are to be erected in locations in which they will be exposed to winds in excess of 90 mph.
In addition, the end wall panel design currently employed in many arch style steel buildings is costly and difficult to manufacture. The present panel is made from a single sheet of metal, has a coverage of 1.5 feet in width and may be up to 191 inches in length (the length of the stock sheet panel) depending on the dimensions of the building. The total flat width of the sheet metal panel (i.e. the width prior to bending) required to create an end wall panel with 1.5 feet of coverage is 23 inches. The metal sheet used to create the panel is cut from a coil of sheet metal. A coil of sheet metal 23 inches wide, which is relatively narrow in width, is costly to manufacture because narrower and thinner coils of sheet metal are more expensive than wider and thicker coils. As such, the most cost effective way to create a 23 inch wide metal sheet is to slit a 46.5 inch wide coil of sheet metal in half. Slitting such a sheet metal coil in half requires outside processing and adds additional steps to the manufacturing process. Also, some material is lost every time a steel panel is slit or cut. A 33 inch wide coil is used to fabricate the arch panels commonly used in steel buildings. In order to reduce costs, it be would desirable to fabricate the end wall panel from a standard size 33 inch wide coil, which is less expensive than cutting a 46.5 inch coil in half. As such, an arch-style metal building manufacturer would only have to purchase a single coil size (33 inch wide) to fabricate the primary components of an arch-style steel building.
Another drawback of current end wall panels is their “coverage dimension.” Current end wall panels customarily have a coverage dimension of about 1.5 feet. This makes installation of the end wall panel into many standard sized arch-style steel buildings expensive and difficult. The difficulty arises from the size of industry standard entryways. Many standard end wall entryway (e.g. door) sizes do not correspond to the one and one-half feet coverage dimension of the commonly used end wall panel. Thus, filler panels must be installed to enable a flush fit for the entryway enclosure. For example, if a cutout is ten feet wide, six one and one-half feet wide end wall panels will cover nine feet of the end wall width above the cutout. This will not accommodate a standard size closure. When the closure is installed, a one foot gap will remain above the cutout, and a one foot wide filler panel must be fabricated and installed to fill in the gap. Fabricating and installing a custom sized filler panel increases the production cost of the building. In addition, the filler panels detract from the aesthetic quality of the arch-style steel building.
In the past, there have been several attempts to provide light-weight structural panels for steel buildings. One such building panel is disclosed in U.S. Pat. No. 2,873,008 of Ashman. The Ashman structural panels are fabricated from metal sheet and have a corrugated section (element 5 on Ashman FIGS. 1 and 2) and a wing section (element 6 on Ashman FIGS. 1 and 2). The corrugated section consists of a plurality of troughs of equal depth. The wing section is a flange extending from the outer side of an outermost trough of the corrugated section. The Ashman panel would likely require additional framework installed behind the panels to meet high-wind requirements. The wing section also increases the amount of material required to fabricate a building resulting in a low strength to weight ratio.
U.S. Pat. No. 3,968,603 of Merson discloses a panel for prefabricated metal buildings. Merson discloses a U-shaped corrugated panel comprised of a bottom wall with a plurality of U-shaped ribs. The side walls, which form the outermost edges of the corrugated panel, are longer than the height of the U-shaped ribs of the corrugated panel and have crimped ends. The plurality of U-shaped ribs and side walls add weight to the panel without greatly increasing the panel's strength. As such, the panel has a low strength to weight ratio. In addition, the panels are U-shaped and cannot easily be installed overlapping one another to increase the stiffness of the end wall or arch section of the building.
U.S. Pat. No. 4,358,916 of Lacasse discloses a corrugated metal building structural unit. The structural unit is comprised of one or more longitudinally extending major waves with a plurality of interlinked longitudinally extending wave-like stiffeners superposed on each major wave. Due to the fact that the Lacasse panel has a high density of wave-like stiffeners, the panel requires excess material and has a low strength to weight ratio.
U.S. Pat. No. 3,308,596 of Cooper discloses a panel of one or two major corrugations with minor corrugations on each of the surfaces of the panel. Due to the high level of minor corrugations on each of the surfaces of the panel, the panel requires more material and as a result has a low strength to weight ratio.
It would be desirable to create an end wall panel that has adequate strength for high-wind applications, that would not require an internal framework and that has a higher strength to weight ratio than the prior art end wall panels. It would also be desirable to have an end wall panel that is inexpensive to manufacture and can easily be installed in arch-style steel buildings of varying dimension.